Trithione polyamine reaction products



3,459,664 TRITHIONE POLYAMINE REACTION PRODUCTS Donald J. Anderson, San Anselmo, Califl, assignor to Chevron Research Company, San Francisco, Calif., a corporation of Delaware No Drawing. Filed Apr. 8, 1966, Ser. No. 541,090 Int. Cl. Cm 1/36 U.S. Cl. 25247 8 Claims ABSTRACT OF THE DISCLOSURE Lubricating oil compositions are provided by combining a 1,2-dithiol-3-thione of at least 30 carbon atoms at elevated temperatures with an alkylene polyamine, wherein the alkylene polyamine has from 2 to 3 carbon atoms between a primary amine group and a secondary amine group.

This invention concerns novel compositions which find use as ashless detergents and dispersants in lubricating oils. More particularly, this invention concerns novel basic nitrogen containing compositions which find use as detergents in lubricating oils.

A development of major importance in the lubricating oil additive field has been the use of ashless detergents; that is, metal free compounds which are capable of reducing varnish and sludge deposits in internal combustion engines. An important advantage of these ashless detergents is the avoidance of the formation of ash upon de composition of the detergent in the engine. Thus, valve and combustion chamber deposition with accompanying octane requirement increase is minimized by avoiding the presence of metal salts.

A variety of low molecular weight ashless detergents have been reported in the patent literature. See for eX- ample US. Patent Nos. 3,018,251, which discloses acylated polyamines; 2,764,551, which discloses polyesters containing amino groups; 2,887,452, which discloses urethanes; and 2,371,333, which discloses esters of pentaerythritol.

It has now been found that excellent detergents and dispersants for lubricating oils can be obtained by combining an alkylene polyamine (having at least 2 amino groups) and of at least 2 carbon atoms with a 1,2-dithiol- 3-thione (trithione) of at least about 30 carbon atoms greater than about 400 molecular weight) at elevated temperatures to form at least in part a composition having molecules having a heterocyclic functionality. The composition obtained has both sulfur and nitrogen present in the molecule. The reaction is carried out either neat (in the absence of solvent) or in the presence of an enert solvent.

The composition obtained will generally have molecular weights greater than 450 and generally not greater than 10,000, usually in the range of about 750 to 5,000. The molecules will have from about 2 to 10 nitrogens, more usually from about 2 to 6 nitrogen atoms and at least one sulfur atom. The molecule will have at least one carbon atom chain of at least about 25 carbon atoms and generally not more than 300 carbon atoms, usually ice not more than 200 carbon atoms. The carbon atom chain may be derived by polymerizing olefins of from about 2 to 6 carbon atoms.

While it is not certain what the structural formula of the major product is, the products spectral properties, as well as other information, indicate that the molecule (when a 1:1 mole ratio of reactants is used) may be a p-thiono substituted diazo heterocycle of from 5 to 6 carbon atoms. This molecule has the following formula:

S RCCHC wherein R is an aliphatic hydrocarbon group of at least about 25 carbon atoms, Y is hydrogen, alkyl, aminoalkyl or polyalkylene aminoalkyl and n is an integer of 2 to 3. R will generally have a molecular weight of about 350 to about 5,000. R will be either hydrogen or aliphatic hydrocarbon of from 1 to 12 carbon atoms. Y may have as many as 8 nitrogen atoms, more usually not more than 4 nitrogen atoms.

When a 2:1 ratio of thione to alkylene polyamine (at least 4 nitrogen atoms) is used, Y would be an alkylene amine having a terminal group which is the radical bonded to Y.

Turning now to a consideration of the reactants, the trithione will have the following formula:

wherein R and R are aliphatic hydrocarbyl having a total of from about 27 to 300 carbon atoms, more usually from about 50 to 200 carbon atoms, wherein one of R and R may be hydrogen. Usually, R will be a long chain aliphatic hydrocarbon group, while R will be hydrogen or alkyl of from 1 to 12 carbon atoms, more usually lower alkyl, i.e., alkyl of from about 1 to 6 carbon atoms.

Illustrative compounds include 4-tert.-butyl-5-polyisobutenyl-1,2-dithiole-3-thione, 5-polyethylenyl-1,2-dithiole- 3-thione, 4-methyl-5-polypropenyl-1,2-dithiole-3-thione, etc.

For the most part, the compounds are readily prepared from aliphatic olefins and sulfur by combining the two reactants at elevated temperatures. For a discussion and description of the preparation of trithiones from polyisobutylene and sulfur, see application Ser. No. 518,787, filed Jan. 5, 1966 now matured to US. 3,364,232; also, for a general discussion of the preparation and properties of trithiones, see the article by Phillip S. Landis, Chem. Rev. 65, 237-245 (1965).

Various aliphatic olefins of the designated number of carbon atoms or molecular Weight may be used. Most frequently, these are prepared by the polymerization of low molecular weight olefins, i.e., 2 to 6 carbon atoms, particularly isobutylene. Other olefins include ethylene, propylene, butene-l, etc. The method of polymerization is not critical to this invention and any convenient method may be used.

The alkylene polyamine or polyalkylene polyamine will generally be from about 2 to 24 carbon atoms, more usually of from 2 to 20 carbon atoms. The polyamines will for the most part have the following formula:

wherein A is an alkylene group of from 2 to 6 carbon atoms having from 2 to 3 carbon atoms between the nitrogen atoms, and generally of from 2 to 3 carbon atoms; B is an alkylene group of from 2 to 6 carbon atoms, generally of from 2 to 3 carbon atoms; m is an integer of from to 9, more usually of from 0 to and Y and Y are hydrogen or aliphatic hydrocarbyl of from 1 to 20 carbon atoms. Y and Y may be the same or different. When In is 0, Y must be hydrogen. That is, the polyamines used in this invention must have a primary and a secondary amine group separated by from 2 to 3 carbon atoms.

The polyamines, for the most part, will be divided into two preferred categories: alkylene polyamines and N- alkyl alkylene diamines. For the alkylcne polyamines, usually Y and Y will be hydrogen, although they may be lower alkyl. For the N alkyl alkylene polyamines Y is hydrogen and Y is an alkyl group usually of from about 12 to 20 carbon atoms. The alkylene polyamines will generally be of from 2 to 20 carbon atoms, more usually of from 2 to 12 carbon atoms. The N-alkyl alkylene diamines will generally be of from 14 to 22 carbon atoms, more usually of from 16 to 20 carbon atoms.

As indicated, the preferred groups are alkylene polyamines and N-alkyl alkylene diamines. The alkylene polyamines will be considered first. For the most part, the alkylene polyamines will have the following formula:

wherein B is alkylene of from 2 to 3 carbon atoms, and m is an integer of from 1 to 6.

When the alkylene group has two carbon atoms between the nitrogen atoms, the probable product which is formed has an imidazoline ring; when there are three carbon atoms between the nitrogen atoms, the probable product formed has a tetrahydropyrimidine ring.

Particularly preferred polyamines are ethylene diamine and polyethylene polyamines of the following formula:

wherein m is aninteger of from 1 to 6.

Illustrative alkylene polyamines include ethylene diamine, propylene diamine, isobutylene diamine, diethylene triamine, triethylene tetramine, dipropylene triamine, hexamethylene diamine, tetraethylene pentamine, pentaethylene hexamine, nonaethylene decamine, N,N-dimethyl diethylene triamine, etc.

The N-alkyl alkylene diamines will for the most part have the following formula:

where Y is alkyl of from about to carbon atoms and B is alkylene of from about 2 to 3 carbon atoms. The alkyl groups may be straight or branched chain, but preferably straight chain. They may be saturated or have aliphatic unsaturation. The aliphatic hydrocarbon substituents may be derived from both naturally occurring and synthetic hydrocarbons.

Aliphatic N-alkyl alkylene amines include N-dodecyl ethylene diamine, N-tetradecyl ethylene diamine, N-hexadecyl ethylene diamine, N-octadecyl ethylene diamine, N-eicosyl ethylene diamine, N-tetradecenyl ethylene diamine, N-octadecenyl ethylene diamine, N-tetradecyl propylene diamine, N-hexadecyl propylene diamine, N-

eicosyl propylene diamine, N-hexadecenyl propylene diamine, etc.

Both the trithione and the polyamine need not be single compounds and, in fact, will usually be mixtures of compounds having an average composition. For the most part with the trihione, the molecules will have molecular weights close to the average molecular weight. With the polyamines, the average composition will generally be the major, if not predominant, component in the mixture.

The reaction between the trithione and amine occurs at ambient temperatures (20 C.) but generally elevated temperatures will be used, e.g., in excess of C., usually in the range of about C. to about 170 C. The time for the reaction is dependent on temperature as well as other rate factors. Usually, the time will be from about 1 hour to 12 hours, preferably not more than 8 hours.

The reaction may be carried out at ambient pressures. Generally an inert atmosphere, e.g., nitrogen is maintained over the reaction mixture during the course of the reaction. The order of addition of the materials is not critical and the reaction may be carried out batchwise or continuously.

In carrying out the reaction, from about 0.1 to 2.1 moles of trithione will be used per mole of polyamine. For the most part, the 1:1 product will be desired, and then about equimolar amounts of amine and trithione will be used; although preferably an excess of amine will be present. While large excesses of amine may be used, usually the mole ratio of amine to trithione will not ex ceed 10:1. That is, the usual mole ratio of amine to trithione will be in the range of about 1-10: 1, more usually in the range of about 2-8z1.

The reactants may be brought together neat (in the absence of solvent) or an inert solvent may be used. Various inert solvents include hydrocarbons, both aromatic and aliphatic. Preferably, the solvent will have a boiling point at least as high as the temperature for the reaction. Illustrative solvents include benzene, toluene, xylene, mesitylene, hexane, heptane, octane, etc.

When a solvent is used, the concentration of reactants is not critical. Generally, the reactants may vary from about 5 to 80 weight percent of the reaction solution.

The following examples are offered by way of illustration and not by way of limitation.

EXAMPLE A Into a reaction flask in a nitrogen atmosphere was introduced 160 g. (5 g. atoms) of sulfur and 260 g. of 4-neopentyl-5-tert.butyl-1,2dithiol-3-thione, the mixture heated to 200 C. and 900 g. (approximately 1 mole) of polyisobutylene added over a period of about 1 hour. The temperature was maintained for 12 hours, at the end of which time the temperature was raised to 210 C. and the pressure reduced to about 4-5 mm. Hg. and the volatile material distilled overhead. The residue weighed 1.028 g. An infrared spectrum of the product was consistent with the trithione.

EXAMPLE I Into a reaction flask was introduced 450 g. (0.5 mole) of a polyisobutylene trithione and 378 g. (2.0 moles) of a mixture of polyethylene polyamines having an average composition of tetraethylene pentamine and the mixture heated at 150 C. for about 16 hours. After allowing the mixture to cool, one liter of hexane was added. An effort to wash the mixture with Water failed, and the water was removed by adding benzene and azeotroping the benzene-water mixture.

After heating the remaining product to C. to drive off as much solvent as possible, the mixture was diluted with an equal volume of hexane, warmed, and then a volume of ethanol equal to the volume of hexane added. While keeping this entire mixture warm, 700-800 ml. of water was added with stirring. The stirring was stopped, and the mixture allowed to separate. The aqueous portion Was discarded, and the volatile solvents removed in vacuo at 80-90 C., 5 mm. Hg. The residue weighed 400 g. The infrared spectrum was consistent with an imidazoline being present.

EXAMPLE II Into a reaction flask was introduced 601 g. molesof ethylene diamine and 500 ml. of toluene and the mixture heated to 120 C. To this mixture was slowly added over a period of one hour 1,500 g. (1 mole) of polyisobutylene trithione in one liter of toluene. The mixture was maintained at reflux for 9 hours, allowed to cool and washed with a 50/50 water/ethanol solution. The aqueous phase was discarded and the organic phase dried, filtered and the volatile materials removed in vacuo. The residue weighed 1,300 g. The infrared spectrum was consistent with theimidazoline being present.

A number of other preparations were carried out following the procedures of either Example I or II, the latter difiering mainly in the presence of a hydrocarbon solvent. The following table indicates the reactants, the amounts used and the conditions under which the reaction was carried out.

eneoxy dihydrocarbyl phosphorodithioate may also be used with advantage. Alternatively, a polyisobutylene trithione may be used for about 260 to 1,500 molecular weight in an amount of from about 0.05 to 5 Weight percent of the composition, by itself or in combination with a phosphorodithioate.

The lubricating fluids which may be used with the compounds of this invention (hereinafter referred to as oils) may be derived from natural or synthetic sources. Oils generally have viscosities of from about 35 to 50,000 Saybolt universal seconds (SUS) at 100 F. Among the natural hydrocarbonaceous oils are paraflin base, naphthenic base, asphaltic base and mixed base oils. Illustrative of synthetic oils are: hydrocarbon oils, such as polymers of various olefins, generally of from 2 to 8 carbon atoms, and alkylated aromatic hydrocarbons; and nonhydrocarbon oils, such as polyalkylene oxides, aromatic ethers, carboxylate esters, phosphate esters, and silver TABLE I Polyiso- Analysis, percent butylene, Amine, Temp, Time, Solvents,

Ex. mole mole 0. Hrs. ml. N S

A, 0.2a A, 02. 150 12 4.56 2.68 IV A, 0.20 B, 1 110 4 1.75 3.50 V C, 0.11 A, 0.5 120 1 T, 600- 0.76 VI A,1.0 B,2 fig T, 1.1 4.0 v1r A, 0.75 13,3 1.1 3.96 VIII B, 1.0 C, 5 125 4 T, 800 1.14 2.34

1 A=Approximately 1,000 molecular welaqight; B=Approximately 1,500 molecular weight;

C=Approximately 3,000 molecular weig tetraethylene tetramine.

3 'I Toluene.

EXAMPLE IX Into a reaction vessel was introduced 1,150 g. (1 mole) of polyisobutylene trithione in 500 ml. of toluene and heated to 50 C. To the warm solution was very slowly added 51.2 g. (0.35 mole) of a mixture of alkylene polyamines having as the major component triethylene tetramine dissolved in 500 ml. of toluene. The addition was carried out over eight hours. The mixture was then heated to 115 C. and allowed to reflux for one hour. The product was then washed with a 50/50 ethanol/water solution, followed by drying. The infrared spectrum was consistent with imidazoline formation.

As already indicated, the compounds of this invention find use as dispersants and detergents in oils of lubricating viscosity. They are effective both under the hot temperature conditions of the diesel engine as well as the varying and generally colder conditions of the automobile engine in city driving. When compounded in a lubricating oil for use in an engine, the compounds of this invention will be present in at least about 0.1 weight percent and usually not more than weight percent, more usually in the range of about 2 to 10 weight percent.

Because of the excellent compatibility of the compositions of this invention with lubricating oils, the compositions can be prepared as lubricating oil concentrates. As concentrates, the compounds of this invention will generally range from about 20 to 70 weight percent, more usually from about to 60 Weight percent of the total composition.

A preferred aspect in using the compounds of this invention in lubricating oils is to include in the oil from about 1 to mM./kg. of an 0,0,-dihyrocarbyl phosphorodithioate, particularly the zinc salt, wherein the hydrocarbyl groups are of from about 4 to 36 carbon atoms. Usually, the hydrocarbyl groups will be alkyl or alkaryl. Other phosphorodithioates such as trialkyl or polyethylesters. The preferred media are the hydrocarbonaceous media, both natural and synthetic.

The above oils may be used individually or together, whenever miscible or made so by the use of mutual solvents.

Other additives may also be included in the oil such as pour point depressants, oiliness agents, antioxidants, rust inhibitors, bearing corrosion inhibitors, other detergents, etc. Usually, for oils to be used in an engine, the total amount of these additives will range from about 0.1 to 10 weight percent, more usually from about 0.5 to 5 weight percent. The individual additives may vary in amount from about 0.01 to 5 weight percent of the total composition. In concentrates, the weight percent of these additives will usually range from about 0.3 to 30.

In order to demonstrate the excellent effectiveness of the compounds of this invention, a number of the compositions prepared were tested in the 1-G Caterpillar Test (MIL-b45199 conditions). The oil used was a Mid- Continent SAE 30 oil and different oxidation inhibitors were used.

The land deposits are rated on a scale of 0 to 800: 0 is completely clean and 800 is completely black. Base oil containing 12 mM./kg. of zinc di(alkylphenyl) phosphorodithioate (the alkyl groups were polypropylene of about 12 to 15 carbon atoms) is rated as 500-800430. The groove deposits are rated on a scale of 0 to 0 is completely clean and 100 is almost completely filled. Base oil containing the indicated amount of phosphorodithioate is rated as 93-15-5-3. The underhead rate deposits are rated on a scale of 0 to 10: 0 is completely black, while 10 is completely clean.

The following table indicates the composition used, the oxidation inhibitor used and the amounts, the time for which the run was carried out and the results.

TABLE II Oxidation l Inhibitor Groove Land Under- Ex. Percent Wt. Percent mMJkg. Hours Deposits Deposits head vr 5 A, 5 so 32-2-00 85-10-11 7. VII 7 B 12 60 28-8-0-0 35-15-15 0. 0 120 46-9-0-0 255-20-25 8. 0

VIII 7 B 12 60 13-4-0-0 1330-15-20 6.

A=Polyisobutyleno trithione of approximately 1,100 molecular weight; B=Zn dipolypropylonephenyl dithiophosphate (polypropylene of from 12 to 15 carbon atoms).

As a further test of the usefulness of the compositions of this invention in lubricating oils, 2. modified F-L-2 test procedure, as described in June 21, 1948 report of the Coordinating Research Council, was employed. This test simulates automobile engine performance. A standard procedure requires the maintenance of a jacket temperature of 95 F. and a crankcase oil temperature of 155 F. at 2,500 rpm. and 45 brake horsepower for 40 hours (closely simulating the relatively cold engine conditions which are normally experienced in city driving). At the end of each test, the engine is dismantled and the amount of total sludge (rating of 0 to 50, no sludge being 50), the total varnish (rating of 0 to 50, no varnish being 50) and the clogging of the rings and oil screen (rating of 0 to 100, no clogging being 0) is determined. The above test was modified by increasing the time and periodically raising the oil sump temperature from 165 F. to 205 F. and the water jacket temperature from 95 F. to 170 F.

Without any detergent additive in the oil, the engine is usually inoperable in about 12 hours.

The compositions were prepared using 21 Mid-Continent SAE 30 base stock. Included in the oil besides the detergent was mM./kg. of zinc 0,0-di(alkyl)dithiophosphate (alkyl of from 4 to 6 carbon atoms) and 2 mM./kg. of zinc 0,0-di(alkylphenyl) dithiophosphate (alkyl is polypropylene of from 12 to 15 carbon atoms). The following table indicates the results obtained.

The above results in both the diesel engine and the automobile engine demonstrate the excellent efiectiveness of the compositions of this invention as detergents and dispersants over a wide range of engine conditions. The compositions of this invention not only provide excellent detergency under the very hot conditions of the diesel engine, but also under the varying conditions of the automobile engine. Moreover, the detergents of this invention do not significantly contribute to undesirable side effects, such as corrosion, rust, etc. Furthermore, the compositions of this invention are compatible with a wide variety of other lubricating oil additives, particularly the oxidation inhibitors employed.

The compositions of this invention may also be employed in fuels and other hydrocarbonaceous fluids which require detergency or dispersancy. The detergency capability also provides emulsification properties and, therefore, the compositions of this invention may also be used as emulsifiers.

As will be evident to those skilled in the art, various modifications on this invention can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the following claims.

I claim:

1. A composition of matter having a molecular weight in the range of 450 to 10,000 consisting essentially of the reaction product obtained by contacting at elevated temperatures, a 1,2-dithiol-3-thione of at least about 30 carbon atoms and an alkylene polyamine having at least two amino groups, one primary amino group and one secondary amino group separated from the primary amino group by from 2 to 3 carbon atoms, wherein the alkylene polyamine is present in at least equimolar amount.

2. A composition of matter consisting essentially of the reaction product obtained by contacting at a temperature of at least C. a composition of the formula:

R 0 CR wherein R and R are saturated aliphatic hydrocarbyl of a total of from about 25 to 300 carbon atoms, wherein one of R and R may be hydrogen, with an alkylene polyamine of the formula:

wherein A is an alkylene group of from 2 to 6 carbon atoms having from 2 to 3 carbon atoms between the nitrogen atoms, B is an alkylene group of from 2 to 6 carbon atoms, Y and Y are hydrogen and m is an integer of from 0 to 9, wherein the mole ratio of trithione of alkylene polyamine is in the range of 0.12 to 1.

3. A composition according to claim 1, wherein the mole ratio of polyalkylene polyamine to trithione is in the range of 2-8 to 1.

4. A composition of matter consisting essentially of the reaction product obtained by contacting at a temperature in the range of to C. about one mole of a 1,2- dithiol-3-thione of the formula:

RFC CR wherein R and K have a total of from 50 to 200 carbon atoms, R is saturated aliphatic hydrocarbyl and R is alkyl of from 1 to 12 carbon atoms with from about 1 to 8 moles of an alkylene polyamine of the formula:

9 16 oil of lubricating viscosity and from about 20 to 70 Weight percent of a composition according to claim 1. JAMES PATTEN, Primary EXamlIler References Cited US. Cl. X.R.

UNITED STATES PATENTS 5 260251, 256, 309, 327

3,394,146 7/1968 Hodgson et a1. 260327 

